--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+include "ground/relocation/rtmap_uni.ma".
+include "ground/relocation/rtmap_nat.ma".
+include "ground/relocation/rtmap_after.ma".
+
+(* RELOCATION MAP ***********************************************************)
+
+lemma after_uni_dx: ∀l2,l1,f2. @↑❪l1, f2❫ ≘ l2 →
+ ∀f. f2 ⊚ 𝐔❨l1❩ ≘ f → 𝐔❨l2❩ ⊚ ⫱*[l2] f2 ≘ f.
+#l2 @(nat_ind_succ … l2) -l2
+[ #l1 #f2 #Hf2 #f #Hf
+ elim (rm_nat_inv_xxp … Hf2) -Hf2 // #g2 #H1 #H2 destruct
+ lapply (after_isid_inv_dx … Hf ?) -Hf
+ /3 width=3 by after_isid_sn, after_eq_repl_back0/
+| #l2 #IH #l1 #f2 #Hf2 #f #Hf
+ elim (rm_nat_inv_xxn … Hf2) -Hf2 [1,3: * |*: // ]
+ [ #g2 #k1 #Hg2 #H1 #H2 destruct
+ elim (after_inv_pnx … Hf) -Hf [ |*: // ] #g #Hg #H destruct
+ <tls_xn /3 width=5 by after_next/
+ | #g2 #Hg2 #H2 destruct
+ elim (after_inv_nxx … Hf) -Hf [ |*: // ] #g #Hg #H destruct
+ <tls_xn /3 width=5 by after_next/
+ ]
+]
+qed.
+
+lemma after_uni_sn: ∀l2,l1,f2. @↑❪l1, f2❫ ≘ l2 →
+ ∀f. 𝐔❨l2❩ ⊚ ⫱*[l2] f2 ≘ f → f2 ⊚ 𝐔❨l1❩ ≘ f.
+#l2 @(nat_ind_succ … l2) -l2
+[ #l1 #f2 #Hf2 #f #Hf
+ elim (rm_nat_inv_xxp … Hf2) -Hf2 // #g2 #H1 #H2 destruct
+ lapply (after_isid_inv_sn … Hf ?) -Hf
+ /3 width=3 by after_isid_dx, after_eq_repl_back0/
+| #l2 #IH #l1 #f2 #Hf2 #f #Hf
+ elim (after_inv_nxx … Hf) -Hf [2,3: // ] #g #Hg #H destruct
+ elim (rm_nat_inv_xxn … Hf2) -Hf2 [1,3: * |*: // ]
+ [ #g2 #k1 #Hg2 #H1 #H2 destruct /3 width=7 by after_push/
+ | #g2 #Hg2 #H2 destruct /3 width=5 by after_next/
+ ]
+]
+qed-.
+